Was Chagas disease responsible for Darwin’s illness? The overlooked eco-epidemiological context in Chile

The source of Darwin’s illness has been a contentious issue in the literature for almost 70 years. Different causal factors have been invoked to account for his symptoms, including Chagas disease. The Chagas hypothesis is based upon Darwin’s diary, in which he narrates his experience with kissing bugs, the main vector of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. In this contribution, we examine the consistency of the “Chagas disease hypothesis” in the light of current ecological and epidemiological knowledge of the disease in Chile. According to his diary and letters, during his overland trips, Darwin slept in rural houses and outdoors for 128 days in a “hyperendemic” area for Chagas disease, more than exposing him to kissing bugs. This observation conveys a likely additional source of infection than previously considered, which might reinforce the idea that Chagas disease contributed to Darwin’s manifest physical deterioration.